Methods of and machines for winding spiral springs



1956 w. .1. B. JANSEN 2,774,407

METHODS OF AND MACHINES FCR WINDING SPIRAL SPRINGS 7 Filed April 26 19513 Sheets-Sheet 1 INVENTOR ATTORNEYS.

Dec. 18, 1956 v\ J. B. JANSEN METHODS OF AND MACHINES FOR WINDING SPIRALSPRINGS 3 Sheets-Sheet 2 Filed April 26, 1951 INVENTOR:

BY W v M/6M ATTORNEYS.

Dc. 18, 1956 w. J. B. JANSEN METHODS OF AND MACHINES FOR WINDING SPIRALSPRINGS Filed April 26, 1951 3 Sheets-Sheet 3 1N VENTOR I ATTORNEYS.

United States Patent IWETHODS OF AND MACHINES FOR WINDING SPIRAL SPRINGSWillem J. B. Jansen, Paris, France Application April 26, 1951, SerialNo. 222,973

Claims priority, application Switzerland April 27, 1950 7 Claims. (Cl.153-65) This invention relates to methods of and machines for windingsprings of spiral form, and particularly to methods and machines whichdo not include a mandrel for forming the springs.

Objects of theinvention are to provide methods of and apparatus forwinding springs by forcing a flat band of spring material against andtangentially along spaced surfaces of a shaping tool to bend the bandinto spiral shape. Objects are to provide methods and apparatus of thecharacter stated in which the shaping tool includes at least twoabutments with guiding surfaces for bending the band, and in which theabutments are moved apart during a spring winding operation to increasethe radius of bending as the length of the spring is increased. Otherobjects are to provide spring winding methods and machines in which aflat strip or band of rectangular cross section is forced tangentiallyover four guiding surfaces to bend the strip or band into a flattenedspiral form such that, on relief of the bending force, the wound springassumes the form of an Archimedean spiral.

These and other objects and the advantages of the invention will beapparent from the following specification when taken with theaccompanying drawings, in which:

Figs. 1 and 2 are diagrammatic views showing the relative positions ofspring winding apparatus embodying the invention at the beginning and ata subsequent stage, respectively, in the winding of a spiral spring;

Fig. 3 is a geometrical diagram showing the theoretically appropriaterelative position to which the guiding surfaces of parts of the shapingtool should be moved at different stages in the winding of a spiralspring;

Fig. 4 is a side elevation, as seen with one side plate removed, of ashaping tool for operation in accordance with the Fig. 3 graphicalsolution;

Fig. 5 is a vertical section through the shaping tool as taken onsection line 5--5 of Fig. 4;

Fig. 6 is a side elevation of a winding machine embodying the invention;

Fig. 7 is a fragmentary plan view of the shaping tool and its adjustablesupport;

Figs. 8 and 9 are fragmentary side elevations, with parts in section, ofanother shaping tool assembly embodying the invention and showing,respectively, the apparatus at the start and at a subsequent stage inthe winding of a spring; and

Fig. 10 is a fragmentary side elevation, with parts in section, of amodified form of shaping tool assembly.

In the drawings, the reference numerals 1 and 2 identify the cooperatingrollers of a mechanism for feeding a strip 3 of spring stock ofrectangular cross-section in the direction of the arrow 4. The strip isfed through a nozzle shaped guide 5 and forced against the inclinedguide surface 6 of a shaping jaw 7. The shaping tool includes a guide 8which extends above the jaw 7 and has a shaping surface normal to thedirection of strip feed, and an upper jaw 9 having a guide surfaceinclined oppositely to the guide surface 6 of the lower jaw 7. Eachguide surface deflects and bends the strip material clock- Wise as it isforced against and slides along the guide surfaces, thus forming aclosed loop 10 when, at the start of the winding operation, the jaws 7and 9 are close to each other and are held stationary until the loop iscompleted, Fig. 1.

The radius of curvature is increased when the shaping tool is movedfurther from the feed rolls 1, 2 and the feed nozzle 5 and, at the sametime, the shaping jaws 7 and 9 are moved apart. By a progressiveseparation of the shaping jaws as the shaping tool is moved away fromthe feed rolls, the curvature imparted to the strip material changesprogressively and a spiral spring 11 is formed,

see Fig. 2. The spring diameter is equal to the difference between thefinal spacing y of the shaping tool from the feed rollers and theinitial spacing x. The movements of the parts must of course be properlycoordinated and synchronized in any machine which automatically performsthe winding operation.

The conditions to be fulfilled could be determined mathematically butthey may be adequately analyzed and determined graphically by means ofthe Fig. 3 diagram in which the blocks 7a, 8a, and 9a indicate theinitial positions of the several shaping tool parts, and the blocks 7b,8b and 9b indicate the corresponding final positions. These endpositions correspond respectively to the initial and final bendingcircles a and b for strip material which is forced towards the shapingsurfaces along the same line and in the direction indicated by the arrow12. Several intermediate positions of the parts are shown but are notseparately identified by reference numerals.

All bending circles are tangent to the horizontal line of strip feed andalso to the shaping surfaces in their several positions corresponding tothe individual bending circles. From an initial circle, which can beassumed to be infinitely small and to correspond to point A, a line ABis drawn diametrically through the severalcircles, this line beingperpendicular to the shaping surface of the jaw 9. A line B'C drawnparallel to the direction of strip feed and through the center B ofcircle b will be perpendicular to the surface of guide block 8a and willbisect the angle BB-C between the line AB and a radius B'C perpendicularto theguide surface of the jaw 7. Lines B'D and B'E drawn from thecenter B of the b-circle to the intersections of the surface of guide 8awith the surfaces of the upper and lower jaws 9a, 7a respectively, makeequal angles with the radius B'C, and, it can be proved that theseintersections for all intermediate circles will fall upon straight linesAD and AE respectively.

The lines AD and AE afford a graphical solution for the problem ofdetermining the progressive movements of the parts 7, 8 and 9 of theshaping tool in winding a spiral spring having an inner loop with thecurvature of circle a and an outer spiral turn 13 with the curvature ofcircle b. This solution is accurate, however, only in the case of stripmaterial such as lead having only a small degree of elasticity, and thetheory must be modi fied in view of the high elasticity of the stripmaterial of the springs. The material as bent to arcuate form by the jaw7 and guide member 8 would slide along the shaping jaw 9 with little orno bending when forced towards the shaping tool in the directionindicated by the arrow 12, and the spring would expand greatly whenremoved from the shaping tool. The unstressed form of the spring wouldnot be that of an Archimedean spiral with a uniform spacing betweenadjacent turns but would be that of a logarithmic spiral with a rapidlyincreasing spacing of the turns.

This variation of the spacing of the turns can be compensated to adesired extent by modifying the relative geometry of the parts in suchmanner that the jaw 9 faces.

shaping tool.

functions as a brake on the strip material to press it so .firmlyagainst the shaping surface of the jaw 7 and guide 8 that the limit ofelasticity is surpassed and the required permanent change of form iseffected by the force required to move the strip materialalongthe'shaping sur- The braking action or increased frictionalresistance at the jaw 9. can be obtained in a simple manner byincreasing the normal pressure of the strip material upon the jaw 9, i.e. by increasing the angle between the shaping surfaces of the guide 8and jaw 9 to considerably more than the 45 angle shown in Fig. 3.

V A shaping tool for winding springs from elastic spring material inaccordance with the above analysis is illustr'ated in Figs. 4 and 5. Twoguideplates 14 and 15 are secured to each other in parallel relation byany known means, and have longitudinal grooves 1.6 along their loweropposed surfaces to form a rectilinear'guide for a slide 17which carriesa vertically slotted guide piece 18.

Pins Hand extend through the guide piece slot and through grooves 21.and22 respectively in the guide plates 14, 15., Shaping jaws 23, 24 areslidably supported on the guide piece 18 by the pins 19, 20 respectivelywhich effectvthe desired displacements of the jaws on movement of theslide 17 since the guide grooves 21 and 22 are inclined to the directionof strip feed according to lines A--E and A-D of Fig. 3. 'As shown .inFig. 4, the guide piece 18 forms the central part of the dined at anincluded obtuse angle of, for example, 135

' to the direction of strip feed and has an included angle with theshaping surface of guide member 18 of 135. The shaping surface of thejaw 24 is inclined at an angle of, for example, 30 to the direction ofstrip feed and has an included obtuse angle with the shaping surface ofguide member 18 of 120". Due to this smaller included .angle betweenshaping surfaces, the shaping surface of a jaw 24 provides the brakingor increased frictional resistance referred to above, causing the limitof elasticity of thestrip to be surpassed and the required permanentchange of form to be efiected. A spring 25 is connected between theslide and a pin 26 fixed to guide plates to pin 27, which is fixed tothe slide, in contactwith a pin 28 of mechanism for'synchronizin g theslide tool adjustments to the feed of the spring material. For clarity,the position of slide bar 42 has been shown in dotted lines in Fig. 5.

'A winding machine including the described shaping tool assembly isshown in Fig. 6. A frame 29 carries a strip feed mechanism comprisingrollers 30 and 31, the

. roller 31 being supported by a lever 32 on a rock shaft 33 mounted onthe frame 29, the lever tbeing yieldingly urged counterclockwise by aspring 34 -to press the roller '31 against roller 30. The rollers areconnected by gear tram 30', to rotate in opposite directions and at thesame speed when the lower roller is turned, for example, by a crank arm,not shown, at the rear side of the frame. .The feed rollers force thestrip material 35 to the left,

as shown by the arrow, through a stationary nozzleshaped guide 5' andinto a shaping tool assembly 36 as illustrated in Figs. 4 and 5. Thelever 32 may be tilted to relieve the pressure on the feed rollers bythe spring 34, for example by means of a cable 37 and foot lever bar 42,and its position may be changed by an adjusting screw 43 so that thedistance between the shaping tool and the roller feed may be altered.The shaft 39 carries The shaping surface of the jaw 23 is in-' 2,774,407V V r i a graduated dial 44 for indicating, by referenceito an indexmark 44a fixed to the frame 29, the length of the at the completion of awinding operation and to prevent V draw the slide towards the left, Fig.4, to maintain the material fed into the shaping tool. The gearing fordriving the shaft 39 includes 'a small gear on the shaft of the roller30, a much larger gear on the shaft 39, and a movable gear or clutchoperable in known manner to break the driving connection to reset theslide bar 42 automatic movement of the slide bar when, aswill bedescribed later, the machine is adjusted to wind helical springs. V

A scale 45 is provided on a guide plate of the shaping tool, and apointer 45a is secured to the slide 17, or its pin 27, and moves alongthe scale 45'l0 indicate the position of the slide within the guideplates.

As shown in Figs; 4 and 7, the forward edge of the shaping tool 36 issupported by a plate or disk 46 which, in turn, is carried by a shaft46'journalled on therframe 29 and may be turned angularly to adjust theorientation for winding springs ofdifferent forms are as follows;

For fiat spiral springs, the slide17of the shaping tool 36 is adjustedby the plate 46 into alinementwith the direction of material feed, thefree end of the strip material 35 from reel 38 is inserted between thefeed rollers 30, 31, the free end is bent slightly upward by hand or by,some auxiliary device, and the feed roller 30 is rotated to-force thestrip 35 into the shaping tool. The strip is consecutively bent intocoil form by the three shaping surfaces, and the slide of the shapingtool is moved away from the feed rollers by spring 25 at a rate, withrespect to the strip feed, determined by the shape of the cam '40. Thelengthof the strip introduced into the shaping tool is indicated by thedial 44 and the diameter of the spiral coil can be readfrom the scale45. When the winding operation is completed, pressure is applied to thefoot lever 37' to lift the feed roller 31 so that the shaping tool slidemay be moved away from the feedrollers without feeding additionalmaterial into the shaping tool 36. The wound spring is cut from thestrip 35 and removed from the shaping tool. The machine is reset byopening the drive connection to the cam shaft 39, returning the slidebar 42'to initial position, and re-coupling the gearing.

To wind helical springs, the gear driveto the cam 40 is opened and theslide bar 42 is clamped bythe handwheel 48 and stud 49, thus preventingmovement of the slide and jaws of the shaping tool during the windingoperation. The diameter of the helical springs is'indicated on the scale45, and the pitch of the helix is determined by the angular setting ofthe shaping tool as indicated on the scale 47 Another shaping tool whichincludes a larger number of shaping surfaces and is better adapted foruse with various types of spring material and for the formation ofArchimedean spirals is shown in Figs. 8 and 9. The

shaping tool comprises two stationary jaws 56. and 51 with guide orshaping surfaces 52, 53. respectively, and two movable'shaping members54, 55 with shaping surfaces 56, 57 respectively. The jaws 50, 51 arestationary and may be parts of the machine frame, and the guide face 53coincides with the direction of material'feed and constitutes a bed ortrack along which the spring strip guide surface 56 inclined or tiltedback from the guide surface 53 at a somewhat greater angle than thatbetween the oppositely inclined guide surface 52 and the guide surface53. The jaw 55 has the form of a sleeve slidable on the jaw 54 and withits guide surface 57 approximately normal to the adjacent guide surface56. Feed rollers 58, 59 force strip material 60 along and tangentiallyto the several guide surfaces, and the jaw 55 is moved upwardly on thejaw 54 t the extent permitted by the pin 61 which is fixed to jaw 55 andmoves in a slot 62 of the jaw 54, as the jaw 54 is moved away from thefeed rollers during a winding operation.

-In winding a spiral spring, the free end of the strip material 60 isbent upwards slightly and then forced against the guide surface 56 ofthe jaw 54 by the feed rollers 58, 59. The strip will be bent or coiledas it is forced against and along the guide surfaces 56 and 57 until theturned-over end of the loop is momentarily arrested by the guide surface52, see Fig. 8. The initial spacing of the shaping surfaces 53 and 57 isless than the desired starting diameter of the spiral because of thehigh elasticity of the material. The coefiicient of reduction may beabout 0.6 in the average case, and it is determined experimentally fordifierent spring stock as it varies with the characteristics of thematerials employed. When, for instance, the inner diameter of thewinding is to be mm., the initial spacing between the guide surfaces 53and 57 is set at 3 mm. because the elasticity of the material will openup the winding loop to 5 mm.

The shaping jaws 54 and 55 slide between guide plates, similar to plates14, 15 of Figs. 4 and 5, having slots therethrough at an appropriateangle to receive the pin 61 and lift the jaw 55 as the jaw assembly isautomatically moved away from the feed rollers by a cam mechanismsimilar to that shown in Fig. 6. The final bending of the loops or turnsis effected between the guide surfaces 52 and 53, and the guide surface52 is spaced from the opposed guide surface 56 by substantially thewinding diameter. The coiled material therefore initially has the formof an ellipse which expands to approximately circular form on releasefrom the bending stress since the limit of proportionality is notexceeded.

For spiral springs of larger diameter, the single sliding jaw 55 isreplaced by a plurality of telescoped jaw sec tions 63, 64 and 65 whichare slidable upon the first movable jaw 54', see Fig. 10. Thisconstruction affords a minimum spacing of the jaw sections from thestationary jaw 66 at the initial stage of a winding operation, and awide guiding face at later stages as the jaw sections 64 and 65 aremoved downward on jaw section 63 by springs 67, 68 respectively as theassembly moves away from the feed rollers. Only the inner jaw section 63need be subject to the automatic cam control, as previously described,since the movements of the jaw sections 64 and 65 are such that theirguide surfaces aline with the guide surface of jaw section 63 in theirend positions.

While three telescoped jaw sections are shown in Fig. 10, it will beapparent that the number may be greater or less according to the desiredratio of the diameters of the inner and outer turns of the spiralspring.

It is to be understood that changes may be made in the machine, forexample the shaping tool assembly may be stationary and the feed rollersmay be moved away from it, and that this and other variations fallwithin the spirit and scope of the invention as set forth in thefollowing claims.

I claim:

1. The method of winding spiral springs utilizing a series ofsuccessively arranged abutments having fiat frictional surfaces inclinedwith respect to each other comprising the steps of forcing a strip ofspring material of rectangular cross-section against and tangentially ofa first abutment having a surface inclined at an obtuse angle withrespect to the initial direction of strip travel,

forcing the' strip against a second abutment having a surfaceinclineda't'an angle with respect to the initial direction of'strip-travelsmaller than said first obtuse angle, forcing the stripagainst a third abutment having a surface inclined at an acute and evensmaller angle with respect to the initial direction of strip travel, theincluded angles between said three successive abutment surfaces beingprogressively smaller whereby the frictional resistance of the surfacescauses the strip limit of elasticity to be surpassed resulting inpermanent deformation of said strip to curvilinear form, and finallyrelatively displacing the abutments as the winding progresses toincrease the spacing of the regions of the adjacent pairs of frictionsurfaces contacted by said strip, thereby to increase the springdiameter.

2. A machine for winding spiral springs from a strip of spring materialof rectangular cross-section comprising shaping means to bend the stripreversely to the direction of strip feed to form the strip intocirculinear form of progressively larger diameter and means for forcingsaid strip into said shaping means, said shaping means including aseries of successively arranged shaping abutments having flat frictionalsurfaces inclined with respect to each other, one of said abutmentshaving a surface inclined at an obtuse angle with respect to the initialdirection of strip travel, a second of said abutments having a surfaceinclined at an angle with respect to the initial direction of striptravel smaller than said first obtuse angle, and a third abutment havinga surface inclined at an acute and even smaller angle with respect tothe initial direction of strip travel, the included angles between saidthree successive shaping abutment surfaces being progressively smallerwhereby the frictional resistance of the surfaces causes the strip limitof elasticity to be surpassed resulting in permanent deformation of saidstrip to curvilinear form, and means for automatically moving aplurality of said abutments with relation to the others of said seriesand in synchronism with the strip feed to increase the radius ofcurvature of the bent strip as the winding operation proceeds.

3. A machine for winding spiral springs as defined in claim 2 whereinone of said shaping abutments is a guide member having a guide surfacesubstantially normal to the direction of strip feed and two of saidshaping abutments are shaping jaws slidably movable upon said guidemember.

4. A machine for winding spiral springs as defined in claim 3 whereinsaid shaping means comprises guide plates, a slide movable between saidguide plates in substantially the direction of strip feed and carryingsaid guide member, and means supporting said shaping jaws between saidguide plates for relative movement with respect to each other and tosaid guide plates.

5. A machine for winding spiral springs as defined in claim 4 whereinsaid guide member is provided with a longitudinal slot and saidsupporting means comprises pins carrying said jawsand extending throughthe slot in said guide member, and said guide plates have inclinedgrooves in which the ends of said pins are seated, whereby upon movementof said slide said jaws are moved upon said guide member relative toeach other and to said guide plates.

6. A machine for winding spiral springs as defined in claim 4 includingmeans for moving said slide in substantially the direction of striptravel in synchronism with said strip forcing means.

7. A machine for winding spiral springs as defined in claim 6 whereinsaid slide moving means comprises spring means biasing said slide withinsaid guide plates in the direction of strip travel and control meanscomprising a cam geared to said forcing means and a slide bar connectedto said slide and cooperating with said cam to control the position ofsaid slide with respect to said guide plates.

(References on following page) V 7 References Cited in the file of thispatent UNITED STATES PATENTS f l Green -May 21', 1878 Kirk 'Sept; 11-,1900 5 Herbert Noyl 17, 1908 Fargo 'June 9,- 1914 Knuth Sept. 14, 1926Sargent -2 Feb.'21, 1928 Germany Nov. 9; 1927 V paw-W

